this is an interesting thread.
cast iron block will need preheat, interpass, and post heat after welding.... to do it right.
don't know how long / heavy the front half of the tractor / block is, but it will need some specialized handling.
any chance if the smoking before teardown was white (ie. coolant getting into the chamber)?
see it is sleeved. is this common for your tractor or Ford's in general?
any other cylinder's sleeved?
one thing you still may have a hard time noting is how far down the crack goes, even after you pull the sleeve.
did you do a leak down test on the cooling system?
just a thought.... does this area leak? does this affect engine performance? can you live with it as it is?
ps: our family has done these repairs before on flat heads but on other easy parts of the block. we've cut drums in half and used charcoal for heat treating, temp crayons, and a lot of praying was used. a couple years ago, we did a repair on an '79 kabuta tractor block where a lift point for the bucket separated from the block.
the old man asked me to do the job as he is getting up there in age - I refused because the block wasn't stripped/prepared like it should have.
well Dad ran out to the local "bitch store" (everytime he comes from there, he bitches about them), AKA welding supply store, and bought Ni-Rod @ 8 rods for $38. After grinding a root, he sticked it and as of today it still holds up for it's owner.